1. Field of the Invention
The present invention relates to a liquid crystal display, and more particularly to a liquid crystal display that is capable of preventing damage and wrinkling of optical sheets caused by external vibration or impact.
2. Discussion of the Related Art
Generally, as shown in FIG. 1 and FIG. 2, a liquid crystal module used as a display device in a notebook computer includes a main frame 14 disposed therein with a backlight assembly including a plurality of optical sheets 4, a light guide 6, a reflective sheet 8, a liquid crystal panel 2, a panel guide 12 surrounding the backlight assembly and the edge of the main frame 14, and a top case 10 surrounding the liquid crystal panel 2 and the edge of the panel guide. The main frame 14 is usually made from a molded material. Recently, however, the main frame 14 has been made from a metal having an excellent heatproof property (e.g., aluminum(Al)) consistent with a high-brightness television or a high-brightness monitor. The reflective sheet 8 is positioned at the bottom of the main frame 14, and the light guide 10 and the optical sheets 4 are disposed thereon. The liquid crystal panel 2 is mounted in the main frame 14 in such a manner to be positioned on the optical sheets 4. As shown in FIG. 3, the backlight assembly includes the reflective sheet 8, the light guide 10 and the optical sheets 4. Also, the backlight assembly further includes a lamp 21 opposed to an incidence surface of the light guide 10, and a lamp reflective plate 22 for improving an efficiency of a light emitted from the lamp 21 and being incident to the light guide 10. The optical sheets 4 consist of a diffusion sheet 4a, prism sheets 4b and 4c, and protective sheets 4d and 4e. In the liquid crystal panel, a liquid crystal is injected between two sheets of glass substrates. Polarizers are attached to each sheet of glass substrate. Liquid crystal pixel cells are each arranged in a matrix and are each driven with a thin film transistor (TFT). The panel guide 12 is bent to surround the side of the main frame 14 and the edges of the optical sheets 4. Similarly, the top case 10 is bent to surround the side of the panel guide 12 and the edge of the liquid crystal panel 2. The main frame 14, the panel guide 12 and the top case 10 are assembled by means of a screw (not shown).
In such a conventional liquid crystal module, the optical sheets 4 are secured to the inner side of the main frame 14 by means of double-face adhesive tape (not shown). However, if the liquid crystal module is subject to vibration or impact from the exterior thereof, then the optical sheets may receive damage, such as wrinkling or scratching, because the optical sheets are secured to the main frame 14 only by the double-face adhesive tape. Furthermore, in the process of assembly of the conventional liquid crystal module structure, the backlight assembly is assembled in “reverse”. More specifically, in manufacture of the backlight assembly, the optical sheets 4, the light guide 6 and the reflective sheet 8 are first disposed on the panel guide 12, which has been turned upside down from its position in the final assembly. Thereafter the main frame 14 is disposed on and secured onto the reflective sheet 8. As a result, the conventional liquid crystal module has a problem in that, since the backlight assembly is assembled upside down as mentioned above, the assembly process has a high defect rate and low productivity.